VITAMIN B12
Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. Vitamin B12 works with many other B vitamins to carry out key roles in functions of the human body.
- Together with folate and vitamin B6, cobalamin helps to maintain normal blood homocysteine levels which is important as raised homocysteine is a risk factor for cardiovascular disease. Vitamin B12 is found only in foods of animal origin. One exception is when plant-based foods are fortified.
- In addition, vitamin B12 serves as a co-factor for enzymes involved in the normal function of the nervous system, the formation of red blood cells, and for the metabolism of folate. It is also involved in energy production.
Functions:
- Remember all those cool things folate did by supporting methylation?
Check out our B9 (Folate) post! B12 is needed for ALL of them.
Other Functions:
- Vitamin B12 is required for the development, myelination, and function of the central nervous system; healthy red blood cell formation; and DNA synthesis.
- Vitamin B12 is needed to prevent anemia.
- Vitamin B12 functions as a cofactor for methionine synthase, an enzyme. Methionine synthase catalyzes the conversion of homocysteine to the essential amino acid methionine.
Deficiency:
B12 and Irreversible Nervous System Degeneration:
- B12 deficiency appears to be uniquely dangerous among any of the B vitamin deficiencies because it can cause IRREVERSIBLE nervous system degeneration.
Many of its features are mental:
- Memory loss
- Changes in personality or mood
- In severe cases, delirium or psychosis
Outside the brain, changes generally begin at the feet and work their way up.
These include:
- Incorrect sense of position.
- Tingling, numbness, or the feeling of something crawling on your skin.
- Loss of full control over your movements.
- Being unable to relax your muscles.
- Walking strangely
B12 deficiency can cause a few other things:
- Optic neuritis, which can cause pain and temporary loss of vision in your eyes.
- Visual disturbances.
- Dizziness or faintness upon standing from sudden changes in blood pressure.
- Exercise intolerance from your heart not adjusting properly to accommodate your exertion.
Sources:
Here are a few ways to eat a day's worth of B12 in one sitting:
- 8 grams of liver.
- 8 grams of clams or oysters.
- 8 grams of nori (laver).
Here are a few ways to eat 1/3 of a day's worth at one sitting (so you have to do these three times a day just to break even!):
- 100 grams of meat, poultry or fish.
- 200ml of milk or 100 grams of cheese.
- 100 grams of black trumpet, chanterelle, or shiitake mushrooms.
Note:
Putting age aside, over 70% of all vegetarians and over 90% of all vegans have evidence in their bloodwork of early B12 deficiency. Becoming a vegetarian or vegan dramatically increases the risk of B12 deficiency.
Supplementation:
- HYDROXYCOBALAMIN
This is a major form of B12 in all natural foods. It is the "neutral" B12, not yet tagged to participate in any specific system. I recommend it as the default form of B12.
- ADENOSYL-COBALAMIN
This is a major form found in meat. It's the form that partners with biotin to throw amino acids into the burning, fiery furnace. Unfortunately, it appears that we might need to break off the adenosyl part before getting it to where it needs to go, so this form might not have any specific benefits.
- CYANOCOBALAMIN
This form is not found in natural foods. Ordinarily we use B12 to detoxify cyanide that we are exposed to from cigarette smoke and certain vegetables. We make cyanocobalamin and pee it out. I have not seen any studies on the matter, but I suspect this is lost in the urine at a greater rate than other forms. It's advantage is that it's cheap.
